Bone marrow where is located? Bone marrow: function, structure

One of the most important tissues of our body is blood. It is she who is responsible for the supply of oxygen, that is, the nutrition of all cells, organs and systems. Therefore, it is extremely important to replenish the stocks of cells that form blood (red blood cells, platelets, white blood cells) in time.

The life span of each of these cells is quite small and ranges from 5 days (leukocytes) to 100 days (erythrocytes). This entails the need for constant self-renewal of blood. In the body there are organs that just perform this function.

Human hematopoietic organs

The main structures of the body that perform the function of forming new blood cells include red bone marrow and spleen. The lymphatic system is also one of the parts for which the bone marrow works. Where is this body and what is it, consider below.

The location of the bone marrow in the body

The localization of parts of the body that form blood cells is quite a point. The fact is that the main organs of hematopoiesis - red bone marrow and spleen - are not the same in functionality. So, it is the bone marrow that is the determining and the main one in this matter, therefore its location, quantity and normal work for any human body is very important.

The main places of bone marrow localization are the bones, but not all of them, since the red bone marrow contains only a part of the bones, and the rest is yellow.

Development of the structure

The whole feature of the formation of bone marrow in humans is as follows:

1. The bone marrow is laid and developed from the very beginning of embryonic embryo formation.
2. At the embryo stage and then at the formed fetus, and after birth for several years, all the bones of the body are producers (producers) of blood cells and lymphocytes, that is, all of them are formed by the red bone marrow, where the main mass of young undifferentiated cells is located.
3. Over time, it is replaced by yellow in the composition of all tubular large and small bones of the body.

Thus, it is already clear that the bone marrow can be of two forms: red and yellow.

Characteristics of the yellow bone marrow

It is a fatty substance of a yellowish color formed by cells produced by the body's lipoid tissue. There is no participation in the formation of blood or the formation of cellular structures of immunity. During life, replaces the red brain in many bones, becoming old with age as the main filler of the tubular bones diafizov . The total mass content in the body is about 2.5-3 kg. This is half of the total bone marrow mass. The main function is nutrition and giving bones elasticity. In addition, with large bodily injuries and injuries, the yellow bone marrow can be temporarily replaced by red to restore the function of normal blood circulation.

Structure of red bone marrow

The main component of it is a large mass of undifferentiated and unspecialized cells, called stem cells. This makes this structure unique and very important for human life. The structure of the bone marrow includes two main tissues: the reticular (stroma) and the hemopoietic.

The tissue from which all the elements of the inner composition of the red brain are formed is called the reticular stroma. It fills the entire internal space of bones and contains the following elements:

• A large number of blood vessels, giving it a semi-liquid consistency and red color;
• Cells fibroblasts (producers of fibrin and fibrinogen)
• Endothelial cells.

Along with the reticular tissue in the red bone marrow there are hematopoietic elements - stem cells. They in the process of differentiation and specialization form erythrocytes, lymphocytes, platelets and other blood and lymphatic components.

Thus, in the body there are several places that have bone marrow, where the main hematopoietic tissue is located - a red variety of brain substance.

1. Epiphases of short and long tubular bones.
2. Diaphysis of tubular osteons.
3. Flat bones.
4. Vertebrae.

This location and localization is the norm for an adult.

Cells of red bone marrow

Hemopoietic tissue contains a mass of stem cells, in composition and structure close to embryonic, embryonic. These are very important elements, because all other cells of the body (and their billions) are highly specialized and can never replace other cells in tissues or be re-specialized. But the stem can. Therefore, they are the basis that gives rise to all the blood elements and parts of the lymphatic system.

Cells of the bone marrow form five germs of hemopoiesis, each of which gives rise to one or another element.

1. Erythrocyte sprout forms erythrocytes - red blood cells that perform the basic function of oxygen transport in organs and tissues.
2. The granulocyte sprout forms cells of eosinophils, neutrophils and basophils, which are important structures of the body's immunity, and also make up blood leukocytes.
3. The lymphocytic germ gives rise to lymphocytes - the basis of the lymphatic system.
4. The monocyte germ forms monocytes - immune uniform elements.
5. The megakaryocytic germ gives rise to the life of platelets - one of the main blood cells responsible for clotting.

Thus, the functions of the red bone marrow will depend precisely on the structure of the cells that form it. All of them are vital structures. The disappearance of at least one type of elements leads to severe human diseases, requiring the donation of brain stem cells.

Functions of the bone marrow

The special structure and purpose of the internal component of the flat bones causes their great importance for the organism. In this regard, you can identify several areas in which the bone marrow operates. Its functions are as follows:

1. It is a continuous supplier of young, fresh blood cells, which need updating every day (red blood cells live for about a day, therefore millions of these structures die every day, and replacement is necessary for new ones).
2. They form a whole complex of structures that oppose all foreign particles and bodies in the body, that is, they form the immune system.
3. They control their own cellular elements and destroy unnecessary ones (for example, tumor cells).
4. The maximum limit the self-destruction of cells within the body, which can be caused by pathological processes.

Undoubtedly, the bone marrow is invaluable. Where is the structure still capable of performing such important functions? Nowhere. There are no analogues in the human body anymore. This gives a special significance and uniqueness to the red bone marrow of a person.

Spleen

In the beginning, we mentioned that not only the bone marrow is important in the formation of blood. Yes, the direct formation of a large mass of its cells and the differentiation of stem cells are characteristic only for it. However, there are other organs of hematopoies that help the bone marrow in this function. The main one is the spleen. Consider its main functions:

• It is an erythrocyte depot of the body, if necessary (large blood loss, trauma, etc.), emits a certain amount of these cells into the total blood mass.
• The spleen is a guard, a filter, through which a large mass of blood passes. It is she who neutralizes, eliminates foreign particles, dissolves dead cells. She is an indispensable cleaner of our body.
• Forms monocytes - the structure of the heart tissue.

The spleen itself is small and weighs about 150 grams. It is located above the stomach, slightly to the left of it.

Transplantation

Unfortunately, life presents such problems to a person that it was generally considered impossible to get rid of for a long time. For example, until 1968, blood cancer was considered incurable. The same applies to such ailments as aplastic anemia, lymphoma, bone marrow disease. In these cases, medicine has found the only solution - bone marrow transplantation. The procedure is quite young, complicated due to incomplete study of the consequences and not yet always proceeding without complications. But every year such operations become more and more common and simplified in execution.

Bone marrow transplantation can be of three types:

1. Directly bone substance.
2. Stem cells.
3. Cord blood (blood).

The choice of type depends on the type of disease. Today, all three varieties are widely used. The most important problem faced by specialists is the selection of a donor for the operation. There are a number of indicators on which it should be suitable for the transplant to be successful both for him and for the recipient.

Donor selection

Find a suitable donor for the transplantation of homeopoietic structures can be based on several conditions:

• Coincidence in the blood group (not always the determining value, but very important);
• Absence of serious or chronic diseases in humans, as well as infectious diseases;
• The donor has no mental disorders and hereditary ailments.

The most common candidates for donorship are native people: sisters, brothers, children or parents. But in this case, guaranteed compatibility in tissues is observed only in 25 percent of cases. It is very difficult to determine the ideal source, which will give a healthy bone marrow (photo of how it looks, you can see in the article). Therefore, we have to look for donors among strangers. Such people can be representatives of any nation, country or race.

Types of bone marrow transplantation

There are two main types:

• Autologous transplantation - when stem cells are taken from the patient himself in advance and blocked in special conditions before surgery;
• Allogeneic transplantation - the material is taken from donors, which include all suitable people, including relatives.

According to modern data, the world leadership in the donor base is assigned to Germany and the United States. In Russia there are very few donors, so our patients are transplanted with stem cells from representatives of other nations.